Routine inspection of equipment is critical in most industries in order to ensure safety and optimize performance. For example, in the petroleum industry and related fields, liquids and gases and mixtures thereof are transported via pipelines and these materials are also stored in large tanks.
It is known in this industry that in order to maintain the integrity of pipelines, storage tanks and the like, a sensor device can be employed to inspect such surfaces. In particular, an inspection vehicle can be used to travel across a surface of the target object (e.g., a pipe or tank) and record information about the quality of the pipe wall. A majority of these inspection vehicles use ultrasonic or magnetic sensors to carry out the inspection. Based on the recorded information, any cracks or other deficiencies in the surface being inspected (e.g., pipe wall) can be detected and noted to allow for subsequent remedial action to be taken.
While there are a number of different sensors that can be used in such inspection vehicles, one preferred type of ultrasonic sensor is a dry coupled probe (DCP) that is configured to perform ultrasonic inspection of the surface to measure wall thickness and detect corrosion. Dry coupled probes are typically built in the form of a wheel in which a shaft (axle) is meant to be held fixed since the shaft has the transducer component rigidly embedded in it while an outer tire rotates around the shaft. The shaft of the probe thus must be held and positioned such that the transducer always points at the surface, meaning that the wheel is not titled in its roll and pitch directions.
Thus, one of the challenges in using a DCP is that the probe needs to always be perpendicular (normal) to the surface being inspected and this can be a challenge while the inspection vehicle is mobile and navigating the surface. This is especially difficult since the inspection vehicle can drive circumferentially, longitudinally and helically on a pipe or tank surface which means that the DCP has to be realigned to ensure that the DCP is normal to the surface being inspected regardless of the location of the inspection vehicle.
The present invention is thus directed to a mechanism (device/apparatus) that both normalizes the sensor (e.g., DCP) and also allows the sensor to be lifted off the surface being inspected when inspection is not being performed to avoid unnecessary wear mainly while the inspection vehicle is being steered and/or moved to a different inspection location.